Figure 8

The tyrosine phosphorylated Cas substrate domain competes with endogenous Cas for binding to v- and c-crk. a) Cos-7 cells were transfected with vector alone (lane 1), the Src*/Cas(3'SD) chimera alone (lanes 2 and 3), v-crk alone (lane 4) or the Src*/Cas(3'SD) chimera along with v-crk (lane 5). The Src*/Cas(3'SD) chimera or v-crk was then immunoprecipitated and probed for phosphotyrosine. Note that v-crk normally associates with more Cas when transfected alone compared when transfected with the Src*/Cas(3'SD) chimera. b) Cos-7 cells were transfected with vector (lane 1) or the Src*/Cas(SD) chimera (lane 2). Endogenous c-crk was then immunoprecipitated and probed with anti-phosphotyrosine (top panel) or with anti-c-crk (bottom panel).